In situ chemical reaction method was used to synthesize Cu-ZrO₂ nanocomposite powders. The process was carried out by addition of NH₄(OH) to certain amount of dispersed Cu(NO₃)₂·3H₂O and ZrOCl₂·8H₂O solution. Afterwards, a thermal treatment at 650 °C for 1 h was conducted to get the powders of CuO and ZrO₂ and remove the remaining liquid. The CuO was then reduced in preferential hydrogen atmosphere into copper. The powders were cold pressed at a pressure of 600 MPa and sintered in a hydrogen atmosphere at 950 °C for 2 h. The structure and characteristics were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results showed that the nanosized ZrO₂ particles (with a diameter of about 30-50 nm) was successfully formed and dispersed within the copper matrix. The density, electrical conductivity, mechanical strength measurements (compression strength and Vickers microhardness) and wear properties of Cu-ZrO₂ nanocomposite were investigated. Increment in the weight % of ZrO₂ nano-particles up to 10 wt.% in the samples, caused the reduction in the densification (7.2%) and electrical conductivity (53.8%) of the nanocomposites. The highest microhardness (146.5 HV) and compressive strength (474.5 MPa) of the nanocomposites is related to the Cu-10 wt.% ZrO₂. Owing to the good interfacial bonding between uniformly dispersed ZrO₂ nanoparticles and the copper matrix. The abrasive wear rate of the Cu-ZrO₂ nanocomposite increased with the increasing load or sliding velocity and is always lower than that of copper at any load or any velocity.

Aluminum (Al) composites have been extensively developed for automotive applications due to their high specific strength. Therefore, in this study, an Al-titanium dioxide (TiO₂) nanocomposite was processed using the accumulative roll bonding (ARB) process. The mechanical characteristics of monolithic and nanocomposites specimens made with 0, 1, 2, and 3 wt% TiO₂ nanoparticles as reinforcement were studied at several ARB passes. According to the microstructure of the composites, rolling after five passes achieves a homogenous distribution of reinforcement particles, ultrafine and elongated grains of the matrix. After five ARB passes, the TiO₂ particles were uniformly dispersed. Finally, scanning electron microscopy and energy dispersive spectroscopy revealed that the Al-TiO₂ nanocomposite had an appropriate dispersion of TiO₂ nanoparticles. Vickers microhardness improves as the number of accumulative roll bonding passes increases. Furthermore, after five passes, Vickers microhardness testing revealed that the sample with 3%TiO₂ has the greatest hardness value of 112 HV, which is significantly greater than the 44 HV hardness value of the ARB-processed aluminum. The mechanical properties of the specimens, yield and ultimate strengths, improved with the addition of TiO₂ nanoparticles. Due to good bonding among the components, mechanical parameters such as microhardness and tensile strength were more than three times better than the Al matrix.

This research work aims to fabricate the Al-4 wt.% SiC nanocomposite using the accumulative roll bonding (ARB) technique. Moreover, a finite element model based on real microstructure representative volume element representation and cohesive zone modeling was developed to predict the mechanical response of the produced composites. The results demonstrated that SiC particles were homogenously distributed inside the Al matrix after five passes. The tensile strength and hardness were improved by increasing the number of ARB passes. The microhardness of an Al-4%SiC composite subjected to five ARB passes was increased to 67 HV compared to 53 HV for Al sheets subjected to the same rolling process. Moreover, owing to greater bonding and grain refinement, tensile strength was increased by a factor of three compared to pure Al. The result of the proposed micro-model successfully predicts the experimentally obtained results of the Al–SiC macro composite. The numerically obtained stress–strain curve was comparable with the experimental one. The results also showed that the size of the used RVE was significantly influential in the prediction of the stress–strain behavior.

Cu–ZrO₂ nanocomposites were prepared by an in-situ reactive synthesis of copper nitrate Cu(NO₃)₂ and zirconium oxychloride ZrOCl₂. Zirconia (ZrO₂) was added by 2.5, 5 and 10 wt.% to the Cu matrix to assess its effect on thermal conductivity and thermal expansion behavior. The results showed that ZrO₂ nanoparticles (30–50 nm) were homogeneously distributed in the copper matrix. The measured thermal conductivity for the Cu–ZrO₂ nanocomposites decreased from 372.8 to 94.4 W m⁻¹ K⁻¹ with increasing ZrO₂ content from 0 to 10 wt.%. Cu-10 wt.% ZrO₂ nanocomposite yields a low thermal conductivity of 94.4 W · m⁻¹ K⁻¹ along with a low coefficient of thermal expansion, 11.47 × 10⁻⁶ K⁻¹.